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The OCKHAM ProjectAnd Digital Library Services

Registries

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• History and Context of the OCKHAM Initiative

• The funded NSF/NSDL Grant

• OCKHAM Services

• OCKHAM Registry

• Future OCKHAM

emory ▪ notre dame ▪ oregon state ▪ virginia tech

emory ▪ notre dame ▪ oregon state ▪ virginia tech

Four Goals:

1) Reference Model

2) New Services (including registry)

3) Adoption of Services / Registry

4) Dissemination and Community Building

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Reference Model

DLServicesRegistry Service ProviderService Accepter

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Initial OCKHAM Services

1) Digital Library Services Registry

2) Alerting Service

3) Browsing Service

4) Harvest-to-Query Service

5) Conversion Service

6) Cataloging Service

7) Pathfinding Service

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Harvest-to-Query (H2Q)

OAI

OAI

OAI

Z39.50SRUSRW

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P2P Registry(aka Distributed Registry)

•Digital Library Services Registry•DNS for Digital Library Services•Distributed to promote extensibility and scalability•Uses IESR Metadata Model•Enables Machine-to-Machine Functionality

•Service-to-Service•Auto-discovery•Intrastructure

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OCKHAM Registry

Architecture Overview

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Design Goals

• Broad compatibility with existing technologies: OAI, Z39.50, Http

• Modular design to allow extensibility

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Registry Architecture

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Data LayerRelational Db & OJB• Synchronized• Database

Interchangeability• Ease of development

Lucene• Fast indexing• “on the fly” indexing• Flexible query engine

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Interface LayerCurrent Interfaces• Struts powered J2ee

interface • OAICat - OAI-PMH 2.0

Future Interfaces• SRU/W • Z39.50

Output Formats• Html• XML

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Clients• Web browser• OAI-PMH • Z39.50• Any web enabled

application.

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Network Layer• JXTA provides low level

network functionality– Peer identification and

discovery– Transport layer

• PeerManager provides modular application level functionality

– Load Management– Client/Server Modules

• Main Registry Modules– URL Server– Harvester Client

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Using OAI For Propagating Data

• A peer can query any other peer and receive an incremental update

• Queries are based on the latest record modification date for the peer’s local copy of the set

• Subsequent queries will use the new latest record modification date

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Hierarchal Network Topology

Topology Requirements• Data must propagate to all

peers• Compensation for inherent

instability of P2P networks• Scalable structure• Low overhead• DNS for Digital Library

Services

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Put the pieces together

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OCKHAM Future

•Expand the DLSR Community and Use•Explore and build DLSR-aware tools and services•Examine personal use of the DLSR•Continue to collaborate with IESR